Add opt-in ~/ asset-path expansion for Razor components (compiler)

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/AssetPathMetadata.cs

@@ -0,0 +1,35 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Razor.Utilities;
+
+namespace Microsoft.AspNetCore.Razor.Language.Components;
+
+// Descriptor-level metadata that records a single element/attribute pair for which the runtime
+// has opted into '~/' asset-path expansion via [AcceptsAssetPath(element, attribute)].
+public sealed record AssetPathMetadata() : MetadataObject(MetadataKind.AssetPath)
+{
+    public required string Element { get; init; }
+    public required string Attribute { get; init; }
+
+    internal override bool HasDefaultValue => false;
+
+    private protected override void BuildChecksum(in Checksum.Builder builder)
+    {
+        builder.Append(Element);
+        builder.Append(Attribute);
+    }
+
+    public ref struct Builder
+    {
+        public string? Element { get; set; }
+        public string? Attribute { get; set; }
+
+        public readonly AssetPathMetadata Build()
+            => new()
+            {
+                Element = Element.AssumeNotNull(),
+                Attribute = Attribute.AssumeNotNull(),
+            };
+    }
+}

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/ComponentsApi.cs

@@ -20,6 +20,7 @@ public static class ComponentBase
         public const string MetadataName = FullTypeName;
 
         public const string BuildRenderTree = nameof(BuildRenderTree);
+        public const string Assets = nameof(Assets);
     }
 
     public static class ParameterAttribute
@@ -161,6 +162,22 @@ public static class EventHandlerAttribute
         public const string FullTypeName = "Microsoft.AspNetCore.Components.EventHandlerAttribute";
     }
 
+    public static class AssetPathAttribute
+    {
+        public const string FullTypeName = "Microsoft.AspNetCore.Components.AssetPathAttribute";
+        public const string MetadataName = FullTypeName;
+    }
+
+    public static class AcceptsAssetPathAttribute
+    {
+        public const string FullTypeName = "Microsoft.AspNetCore.Components.AcceptsAssetPathAttribute";
+        public const string MetadataName = FullTypeName;
+
+        // Name of the public type the runtime decorates with [AcceptsAssetPath] declarations;
+        // the compiler discovers it by name to build the asset-path allowlist.
+        public const string CandidateTypeName = "AssetPathAttributes";
+    }
+
     public static class ElementReference
     {
         public const string FullTypeName = "Microsoft.AspNetCore.Components.ElementReference";

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/PropertyMetadata.cs

@@ -17,6 +17,7 @@ public sealed record PropertyMetadata() : MetadataObject(MetadataKind.Property)
     public bool IsGenericTyped { get; init; }
     public bool IsInitOnlyProperty { get; init; }
     public bool AcceptsStringLiteral { get; init; }
+    public bool AcceptsAssetPath { get; init; }
 
     internal override bool HasDefaultValue => Equals(Default);
 
@@ -30,6 +31,7 @@ private protected override void BuildChecksum(in Checksum.Builder builder)
         builder.Append(IsGenericTyped);
         builder.Append(IsInitOnlyProperty);
         builder.Append(AcceptsStringLiteral);
+        builder.Append(AcceptsAssetPath);
     }
 
     public ref struct Builder
@@ -42,6 +44,7 @@ public ref struct Builder
         public bool IsGenericTyped { get; set; }
         public bool IsInitOnlyProperty { get; set; }
         public bool AcceptsStringLiteral { get; set; }
+        public bool AcceptsAssetPath { get; set; }
 
         public readonly PropertyMetadata Build()
             => new()
@@ -54,6 +57,7 @@ public readonly PropertyMetadata Build()
                 IsGenericTyped = IsGenericTyped,
                 IsInitOnlyProperty = IsInitOnlyProperty,
                 AcceptsStringLiteral = AcceptsStringLiteral,
+                AcceptsAssetPath = AcceptsAssetPath,
             };
     }
 }

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/MetadataObject.cs

@@ -14,7 +14,8 @@ public enum MetadataKind : byte
     Bind,
     Component,
     EventHandler,
-    ViewComponent
+    ViewComponent,
+    AssetPath
 }
 
 public abstract record MetadataObject

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperKind.cs

@@ -17,5 +17,6 @@ public enum TagHelperKind : byte
     Ref,
     Splat,
     FormName,
-    RenderMode // Last component kind. If another is added, update TagHelperKindExtensions.IsAnyComponentKind.
+    RenderMode,
+    AssetPath // Last component kind. If another is added, update TagHelperKindExtensions.IsAnyComponentKind.
 }

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperKindExtensions.cs

@@ -8,7 +8,7 @@ public static class TagHelperKindExtensions
     extension(TagHelperKind kind)
     {
         public bool IsAnyComponentKind
-            => kind is >= TagHelperKind.Component and <= TagHelperKind.RenderMode;
+            => kind is >= TagHelperKind.Component and <= TagHelperKind.AssetPath;
 
         public bool IsComponentOrChildContentKind
             => kind is TagHelperKind.Component or TagHelperKind.ChildContent;

src/Razor/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelpers/Producers/TagHelperProducerKind.cs

@@ -16,5 +16,6 @@ internal enum TagHelperProducerKind : ushort
     Splat,
     MvcViewComponent,
     Mvc1_X_ViewComponent,
-    Mvc2_X_ViewComponent
+    Mvc2_X_ViewComponent,
+    AcceptsAssetPath
 }